1. Field of the Invention
Various embodiments of the present invention relate to a method and apparatus for providing safety protection in an additive manufacturing device.
2. Description of Related Art
Freeform fabrication or additive manufacturing is a method for forming three-dimensional articles through successive fusion of chosen parts of powder layers applied to a worktable.
An additive manufacturing apparatus may comprise a work table on which said three-dimensional article is to be formed, a powder dispenser, arranged to lay down a thin layer of powder on the work table for the formation of a powder bed, an energy beam for delivering energy to the powder whereby fusion of the powder takes place, elements for control of the energy given off by the energy beam over said powder bed for the formation of a cross section of said three-dimensional article through fusion of parts of said powder bed, and a controlling computer, in which information is stored concerning consecutive cross sections of the three-dimensional article. A three-dimensional article is formed through consecutive fusions of consecutively formed cross sections of powder layers, successively laid down by the powder dispenser.
An additive manufacturing apparatus comprises inter alia a beam source, a powder distributor and other mechanically moving parts which, if not securely switched off, may be harmful to an operator or service personnel. One way of making sure that the machine is safe to work with is to manually switch off the power supply to the additive manufacturing device. A problem with a completely dead device is that even the non-harmful devices are not working which may be annoying and/or problematic in some situations. Another problem is that the power switch may be forgotten to be switched off.
Additive manufacturing may also require a safe powder handling and a safe recirculation of unused powder material, meaning that only certain types of powder suction devices are allowed to be used which do not expose the powder of any kind of igniting means. Safe powder handling may also incorporate the insurance that the recirculated powder is clean from any foreign impurities which may destroy the performance of the manufactured three dimensional article, which in turn may cause a safety problem where the final article end up. Recirculated powder may be non-solidified or non-fused powder material from a previous process which is reused in a latter process. Said recirculated powder may be blended with virgin powder.